Mask and method of manufacturing array substrate using the same

ABSTRACT

A mask includes: a substrate that includes a central area and a peripheral area disposed around the central area; and lenses disposed in rows and columns, in the central area and the peripheral area. The lenses of opposing sides of the peripheral area may be disposed in different rows or columns. For a given amount of input light, the lenses of the peripheral area may focus less light on a substrate than the lenses of the central area. The mask may be disposed over the substrate in different positions, and then the substrate may be irradiated through the mask, while the mask is in each of the positions. The peripheral portion of the mask may be disposed over the same area of the substrate, while the mask is in different ones of the positions.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 2011-0006652, filed on Jan. 24, 2011, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Exemplary embodiments of the present invention relate to a mask and amethod of manufacturing an array substrate using the mask.

2. Description of the Related Art

Generally, a liquid crystal display (“LCD”) panel may include an arraysubstrate, an opposite substrate facing the array substrate, and aliquid crystal layer interposed between the array substrate and theopposite substrate. A plurality of switching elements for driving pixelareas may be formed on the array substrate. The LCD panel may display animage by applying an electric field to the liquid crystal layer.

The array substrate and the opposite substrate include a plurality ofpixels arranged in a matrix. Each of the pixels includes at least onethin-film transistor (“TFT”) for driving the pixel. The TFT includes agate electrode, a semiconductor layer, a source electrode, and a drainelectrode. One pixel includes at least one TFT. The TFT is located in anon-display area where an image is not formed. Thus, an aperture ratiois decreased by the non-display area. Moreover, when multiple TFTs areformed within one pixel, an aperture ratio is further decreased.

In a manufacturing process of an array substrate, a semiconductor layerof the TFT is formed by crystallizing an amorphous silicon layer. Duringthe crystallization, the amorphous silicon layer coated on the entirearray substrate is crystallized, and then unnecessary portions areremoved. When the amorphous silicon layer is crystallized, a laser isgenerally radiated onto the entire array substrate, which can be a timeconsuming process. Thus, an improved manufacturing method of an arraysubstrate is needed, which is capable of processing the crystallizationrapidly and effectively.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention provide a mask used tocrystallize a silicon layer, so as to improve the display quality of apanel.

Exemplary embodiments of the present invention also provide a method ofmanufacturing an array substrate using the above-mentioned mask.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

Exemplary embodiments of the present invention also provide a mask thatincludes a substrate that includes a central area and a peripheral area,lenses disposed in the central and peripheral areas, and alight-blocking layer disposed between the lenses.

According to another aspect of the present invention, provided is a maskthat includes a substrate that includes a central area and a peripheralarea; first lenses disposed in the central area and second lensesdisposed in the peripheral area. For a given amount of input light, thefirst lenses may focus more light than the second lenses. The secondlenses may be half-tone lenses.

According to still another aspect of the present invention, there isprovided a method of manufacturing an array substrate. In the method,gate wiring and gate electrodes connected to the gate wiring are formedon a base substrate. Amorphous silicon layers are coated on the gateelectrodes. A mask is disposed a mask in different positions over thesubstrate, the mask comprising a central area, a peripheral areadisposed around the central area, and lenses disposed in the centralarea and the peripheral area. The amorphous silicon layers areirradiated through the mask, while the mask is in each of the positions,to sequentially crystallize the amorphous silicon layers. Sourceelectrodes and drain electrodes are formed on the crystallized siliconlayer.

According to some exemplary embodiments of the present invention, laserlight is condensed through lenses formed on a mask to crystallizeamorphous silicon, thereby increasing an electron mobility of TFTsformed on a pixel area, so that the TFTs may be formed in a small size.Thus, a space occupied by the TFTs within pixels may be decreased, sothat an aperture ratio of the pixels may be greatly enhanced.

Moreover, the appearance of brightness variations between differentgroups of pixels can be reduced, by crystallizing the silicon layers atthe borders of adjacent groups in different operations. Thus, luminancedifferences due to differences in laser intensity may be obscured,thereby reducing the incidence of defective displays.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a pan view showing a mask according to an exemplary embodimentof the present invention.

FIG. 2 is a cross-sectional view taken along a line I-I′ of FIG. 1.

FIG. 3 is a plan view showing an array substrate manufactured by usingthe mask of FIG. 1.

FIG. 4 is a partial enlarged plan view of portion ‘X’ of FIG. 3.

FIG. 5 is a partial enlarged plan view of portion ‘Y’ of FIG. 4.

FIGS. 6A, 6B, 6C, and 6D are cross-sectional views showing a method ofmanufacturing an array substrate using the mask of FIG. 1.

FIG. 7 is a plan view showing an area of the mask of FIG. 1.

FIGS. 8, 9 and 10 are plan views showing an appearance in which the maskof FIG. 1 is used.

FIGS. 11A, 11B, and 11C are plan views showing the movement of the maskof FIG. 1 across an array substrate.

FIG. 12A is a plan view showing an array substrate crystallized usingthe mask of FIG. 1.

FIG. 12B is a partial enlarged plan view showing a portion of the arraysubstrate of FIG. 12A.

FIG. 13 is a plan view showing a mask, according to another exemplaryembodiment of the present invention.

FIG. 14 is a cross-sectional view taken along a line II-IF of FIG. 13.

FIG. 15 is a plan view showing areas of the mask of FIG. 13.

FIGS. 16 and 17 are plan views showing movements of the mask of FIG. 13.

FIGS. 18A, 18B, 18C, and 18D are plan views showing modifications of themask of FIG. 13.

FIG. 19A is a plan view showing an array substrate that is crystallizedusing the mask of FIG. 13.

FIG. 19B is a partial enlarged plan view showing a portion of an arraysubstrate of FIG. 20A.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which exemplary embodiments of the inventionare shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these exemplary embodiments areprovided so that this disclosure is thorough, and will fully convey thescope of the invention to those skilled in the art. In the drawings, thesize and relative sizes of layers and regions may be exaggerated forclarity. Like reference numerals in the drawings denote like elements.

It will be understood that when an element or layer is referred to asbeing “on” or “connected to” another element or layer, it can bedirectly on or directly connected to the other element or layer, orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on” or “directly connected to”another element or layer, there are no intervening elements or layerspresent.

FIG. 1 is a pan view showing a mask 100, according to an exemplaryembodiment of the present invention. FIG. 2 is a cross-sectional viewtaken along a line I-I′ of FIG. 1. Referring to FIGS. 1 and 2, the mask100 includes a substrate 10 that includes a central area 11 and aperipheral area 12 disposed around the central area 11. The substrate 10may be rectangular or square-shaped. First areas 21 including atransmitting portion, second areas 22 including a non-transmittingportion, and a plurality of lenses 30 are formed on the substrate 10.

In this exemplary embodiment, the light-blocking layer 40 is used toprevent light from exiting portions of the substrate 10. Alternatively,the substrate 10 may be formed from an opaque material. When thesubstrate 10 is opaque, the lenses 30 may be disposed in slits or holesformed in the substrate 10 and the light-blocking layer 40 may beomitted.

Each of the lenses 30 focuses laser light incident thereto, onto an areato be crystallized. The light-blocking layer 40 prevents unfocused lightfrom exiting the substrate 10.

Referring again to FIG. 2, the substrate 10 includes the central area11, the peripheral area 12, the lenses 30, and the light-blocking layer40. The substrate 10 may include a transparent material, such as glass,plastic, or the like.

The light-blocking layer 40 is formed on the substrate 10 to block thelaser light. The light-blocking layer 40 covers a surface of thesubstrate 10, except for where the lenses 30 formed. The light-blockinglayer 40 may include a metallic material. The substrate 10 and thelenses 30 may be integrally formed.

The lenses 30 are formed on the substrate 10, and then thelight-blocking layer 40 is formed between the lenses 30 to complete themask 100. Alternatively, the light-blocking layer 40 may be formed on anopposing surface of the substrate 10.

Thus, the mask 100 focuses laser light onto amorphous silicon layers ofan array substrate, to crystallize the silicon layers. The mask 100 isformed to have a smaller size than an array substrate. Thus, the mask ismoved with respect to the array substrate, to crystallize differentareas thereof.

FIG. 3 is a plan view showing an array substrate manufactured using themask of FIG. 1. Referring to FIG. 3, the array substrate 500 includes apixel area 520 and a peripheral area 510.

The pixel area 520 includes pixels arranged in a matrix. The pixels arecrystallized by using the mask 100 (shown in FIGS. 1 and 2), accordingto an exemplary embodiment of the present invention. Since the mask 100is smaller than the pixel area 520, the pixel area 520 is divided intocrystallization areas 530 that are sequentially crystallized by movingthe mask 100.

FIG. 4 is a partial enlarged plan view of portion ‘X’ of FIG. 3.Referring to FIGS. 3 and 4, each of the crystallization areas 530includes a plurality of pixels 521.

The crystallization area 530 is a virtual area corresponding to the mask100. Each of the pixels 521 includes a TFT and a pixel electrode. Thepixels 521 transmit light in accordance with an input signal. The pixelelectrode may be transparent, and the TFT may be opaque. Thus, the TFTmay interfere with light transmission. When the TFT occupies a smallerportion of one pixel 521, an aspect ratio of the pixel 521 is increased,which improves image quality.

FIG. 5 is a partial enlarged plan view of portion ‘Y’ of FIG. 4.Referring to FIG. 5, the pixel 521 includes a gate wiring 621, a gateelectrode 611, a data wiring 620 electrically connected to the gatewiring 621, a source electrode 621, a pixel electrode 630 electricallyconnected to the data wiring 620, a drain electrode 631 spaced apartfrom the source electrode 621 and electrically connected to the pixelelectrode 630, and an active layer 640.

The active layer 640 is formed between the gate electrode 611 and thesource/drain electrodes 621 and 631, to configure a thin-film transistor(TFT). The TFT may control the pixel electrode 630 in accordance with aninput signal. The input signal may be delivered by the gate wiring 621and the data wiring 620.

Each of lenses 30 of the mask 100 is disposed facing one of the activelayers 640 during crystallization. Then a laser is radiated through themask 100 to crystallize the active layers 640. Referring again to FIG.1, laser light is condensed by the lenses 30. Thus, the active layers640 may be crystallized by high density ions.

When the active layer 640 is crystallized by high density ions, theelectron mobility of the active layer 640 is greatly increased. Aconventional TFT active layer has an electron mobility of about 0.5cm²/μs. However, the active layer 640 crystallized by the mask 100 mayhave an electron mobility of up to about 5 cm²/μs. In this case, theactive layer 640 may be smaller, while still having the same capabilityas a larger conventional TFT. As a result, the aperture ratio of thepixel 521 may be greatly increased.

FIGS. 6A, 6B, 6C, and 6D are cross-sectional views showing a method ofmanufacturing the TFT of the pixel 521 shown in FIG. 5. Referring toFIGS. 6A to 6D, the gate electrode 611 is formed on the base substrate520. An insulation layer 612 is formed on the gate electrode 611. Anamorphous silicon layer 641 is formed on the insulation layer 612 facingthe gate electrode 611.

The mask 100 is disposed facing the substrate 520 and laser light isradiated through one of the lenses 30 and onto the amorphous siliconlayer 641. The laser light crystallizes the amorphous silicon layer 641into the active layer 640 having a high electron mobility, so that asmall TFT may be formed. Then the source and drain electrodes 621 and631 are formed on the active layer 640.

The method of FIGS. 6A to 6D is an example of a process for forming aTFT using the mask 100. However, according to various embodiments, themethod and/or mask 100 may be modified in various ways.

FIG. 7 is a plan view further describing the mask 100 of FIG. 1.Referring to FIG. 7, the mask 100 includes the central area 11 and theperipheral area 12. The peripheral area 12 includes a first side 121, asecond side 122, a third side 123, and a fourth side 124. Moreover, theperipheral area 12 may include a first corner 125, a second corner 126,a third corner 127, and a fourth corner 128.

The first side 121 and the second side 122 are disposed on opposingsides of the central area 11 and extend lengthwise, in a first directionD1. The third side 123 and the fourth side 124 are disposed on opposingsides of the central area 11 and extend lengthwise, in a seconddirection D2. The second direction D2 may be substantially perpendicularto the first direction D1.

The first corner 125 is positioned between the first side 121 and thethird side 123, and the second corner 126 is positioned between thethird side 123 and the second side 122. The third corner 127 ispositioned between the first side 121 and the fourth side 124, and thefourth corner 128 is positioned between the second side 122 and thefourth side 124. The first corner 125 includes a lens 30. However, thepresent invention is not limited thereto, as the lens 30 may be disposedin any of the corners 125, 126, 127, and 128.

The lenses 30 are formed in a matrix of rows and columns. However, therows and columns are offset with respect to the peripheral area 12. Inother words, each row includes a lens 30 in only one of the first andsecond sides 121 and 122, and each column includes a lens 30 in only oneof the third and fourth sides 123 and 124. Thus, the lenses 30 disposedin the first side 121 are disposed in different rows than the lenses 30disposed in the second side 122. In addition, the lenses 30 disposed inthe third side 123 are disposed in different columns than the lenses 30disposed in the fourth side 124. As such, the sides 121-124 may bedisposed over the same areas during crystallization, as discussed below.

FIG. 8 is a plan view showing a lateral movement of the mask 100 duringa crystallization process. Referring to FIG. 8, the mask 100 isinitially disposed in position P1, and a laser is radiated through thelenses 30 to crystallize a first group of active layers. The mask 100 isthen moved laterally to position P2, and the laser is radiated throughthe lenses 30 to crystallize a second group of active layers.

The positions P1 and P2 overlap, such that the first and second edges121 and 122 are sequentially disposed in area A, i.e., over the samecolumn of active layers. However, since the lenses 30 of the first andsecond sides 121 and 122 are disposed in different rows, each siliconlayer in area A is irradiated only once.

FIG. 9 is a plan view showing a vertical movement of the mask 100 duringa crystallization process. Referring to FIG. 9, the process is similarto the process of FIG. 8, except that the mask is moved vertically fromposition P1 to position P2. As such, the third and fourth sides 123 and124 of the mask 100 are sequentially disposed in area B, i.e., over thesame row of active layers. Thus, the lenses 130 of the third and fourthsides 123 and 124 are used to crystallize the active layers disposed inarea B. However, since the lenses 30 of the second and third sides 123and 124 are disposed in different columns, each silicon layer of area Bis only irradiated once.

FIG. 10 is a plan view showing a crystallization process that includes acombination of the processes shown in FIGS. 8 and 9. Referring to FIG.10, the mask 100 is moved between positions P1-P4 and underlying siliconlayers are crystallized. The mask 100 may be moved between the positionsP1-P4 in any order. Accordingly, the first and second edges 121 and 122are sequentially disposed in area A, and the third and fourth edges 123and 124 are sequentially disposed in area B. As such, the corners 125,126, 127, and 128 are sequentially disposed in area C, where areas A andB overlap. However, since only corner 125 includes a lens 30, a siliconlayer disposed in area C is only irradiated once.

FIGS. 11A, 11B, and 11C are plan views showing the movement of the mask100 over an array substrate 500. Referring to FIG. 11A, a pixel area 520of the array substrate 5000 is divided into crystallization areas 530.The mask 100 is moved to each of the crystallization areas 530 and alaser is irradiated onto the mask 100. In other words, the mask 100 ismoved along the array substrate in a raster pattern.

When a laser is irradiated onto crystallization areas 530 in differentportions of the array substrate 5000, the strength/intensity of thelaser may vary. The intensity variation may generate a difference in thecrystallization amounts the silicon layers in the crystallization areas530.

As a result, crystallization areas 530 may vary in brightness. Forexample, the different brightness may be emphasized at boundary portionsof the crystallization areas 530. In this case, display defects, such asa horizontal line defect and a vertical line defect, may be displayed onthe pixel area 520. Such defects may result in a panel being defective.

However, according to aspects of the present invention, the siliconlayers at edges of the crystallization areas 530 are crystallized indifferent irradiation operations. Thus, brightness differences betweenactive regions produced in each operation are less noticeable.Therefore, the appearance of line defects is reduced.

FIGS. 11B and 11C are plan views showing the movement of the mask 100 ismoved between different crystallization areas 530 in the pixel area 520of the array substrate 5000. Each of the crystallization areas 530 issequentially irradiated through the mask 100, to form active layers.Referring to FIG. 11B, the mask 100 is moved along the path of FIG. 11A.The third and fourth sides 123 and 124 (shown in FIG. 9) aresequentially disposed in area B. The first and third sides 121 and 124are initially disposed facing the peripheral area 510.

Referring to FIG. 11C, the mask 100 is moved along the path shown inFIG. 11A. The corners 125-128 are sequentially disposed in area C. Sinceonly one of the corners 125-128 includes a lens 30, the silicon layer inarea C is irradiated only once. The process continues until all of thesilicon layers are crystallized.

FIG. 12A is a plan view showing the array substrate 500. Referring toFIG. 12A, irradiation areas 540 having saw tooth-shaped edges are formedon the pixel area 520 of the array substrate 5000. The saw tooth-shapededges are formed due to the offset of the lenses 30 in the peripheralarea 12 of the mask 100, and due to the edges 121-124 of the mask 100being sequentially disposed in the same positions.

FIG. 12B is a partial enlarged plan view showing a portion of an arraysubstrate of FIG. 12A. Referring to FIG. 12B, the include arraysubstrate 5000 includes four crystallization area 540A-540D. Boundaryportions A, B, C and D of the crystallization area 540A-540D areinterlaced. As such, if the intensity of a laser used to irradiate thecrystallization areas 540A-540D varies, such that the light produced bythe crystallization areas 540A-540D varies in intensity, the interlacingof the boundary portions A, B, C and D obscures the changes inbrightness. In other words, the visibility of brightness variations isreduced.

In the peripheral area 12 of the mask 100, one column or row of thelenses 30 is formed in each of the first to fourth sides 121-124.However, according to some aspects, the lenses 30 may arranged inmultiple columns or rows in all or some of the first to fourth sides121-124. In addition, the lenses 30 may be disposed randomly within thefirst to fourth sides 121-124, so long as opposing sides havecorresponding lens patterns.

When the lenses 30 are arranged in the first to fourth sides 121, 122,123, and 124 and the first to fourth corners 125, 126, 127, and 128 in arandom pattern, the lens pattern of the first side 121 should be inverseto the lens pattern of the second side 122, and the lens pattern of thethird side 123 should be inverse to the lens pattern of the fourth side124.

Each of the first and second sides 121 and 122 is irradiated whendisposed in area A, and each of the third and fourth sides 123 and 124is irradiated when disposed in area B. Moreover, each of the first tofourth corners 125, 126, 127 and 128 is irradiated when disposed in areaC.

FIG. 13 is a plan view showing a mask 200, according to anotherexemplary embodiment of the present invention. FIG. 14 is across-sectional view taken along a line II-II′ of FIG. 13. Referring toFIGS. 13 and 14, the mask 200 is similar to the mask 100, so only thedifferences therebetween will be described in detail.

The mask 200 includes a substrate 210, first areas 221 and second areas222. The substrate 210 also includes a central area 211 and a peripheralarea 212 disposed around the central area 211. Lenses 230 are disposedin a matrix of rows and columns in the central area 211, and lenses 231are disposed the rows and columns in the peripheral area 212. A lightblocking layer 240 is disposed on the substrate between the lenses 230and 231.

A partial light-blocking layer 250 is disposed on the lenses 231. Thepartial light-blocking layer 250 may form a grating or grid. As such,the lenses 231 are partially covered, and may be referred to ashalf-tone lenses. For example, about half of the light transmitted tothe lenses 231 passes therethrough. In other words, the partiallight-blocking layer 250 may prevent about half of the light transmittedto the lenses 231 from being focused thereby.

Thus, active layers disposed below the lenses 231 receive about half ofthe light that is received by active layers disposed below the lenses230 of the central area 211. As such, active layers disposed below thelenses 231 can be irradiated twice, before being completelycrystallized. As a result, the lenses 231 are not offset on opposingsides of the central area 211.

The partial light-blocking layer 250 may be formed from a same materialas the light-blocking layer 240. For example, the light blocking layer240 may be formed on the lenses 231, and then partially removed by, forexample, etching to form the partial light-blocking layer 250. As such,the partial light-blocking layer 250 may have a halftone pattern.

The substrate 210 and the lenses 230 and 231 may be integrally formed.The lenses 230 and 231 are formed on the substrate 210, and then thelight-blocking layer 240 is formed therebetween.

Alternatively, the light-blocking layer 240 may be formed on anothersurface of the substrate 210, on which the lenses 230 and 231 are notformed. The partial light-blocking layer 250 may be formed on anothersurface of the substrate 210. Each of the light-blocking layer 240 andthe partial light-blocking layer 250 may be formed on different surfacesof the substrate 210.

In the present exemplary embodiment, the light-blocking layer 240 andthe partial light-blocking layer 250 are used to prevent unfocused lightfrom passing through the substrate 210. Alternatively, the substrate 210may be formed from an opaque material.

When the substrate 210 is opaque, the lenses 230 and 231 may be disposedon slits or holes formed in the substrate. When the substrate 210 isopaque, the light-blocking layer 240 may be omitted.

FIG. 15 is a plan view showing the mask 200 of FIG. 13. Referring toFIG. 15, the peripheral area 212 includes a first side 2121, a secondside 2122, a third side 2123, and a fourth side 2124. Moreover, theperipheral area 212 includes a first corner 2125, a second corner 2126,a third corner 2127, and a fourth corner 2128.

The first side 2121 and the second side 2122 are disposed on opposingsides of the central area 211 and extend lengthwise, in a firstdirection D1. The third side 2123 and the fourth side 2124 are disposedon opposing sides of the central area 211 and extend lengthwise, in asecond direction D2. The second direction D2 may be substantiallyperpendicular to the first direction D1.

The first corner area 2125 is positioned between the first side 2121 andthe third side 2123, and the second corner area 2126 is positionedbetween the third side 2123 and the second side 2122. The third cornerarea 2127 is positioned between the first side 2121 and the fourth side2124, and the fourth corner area 2128 is positioned between the secondside 2122 and the fourth side 2124.

The first and second sides 2121 and 2122 may be formed to havesubstantially the same shape, and the third and fourth sides 2123 and2124 may be formed to have substantially the same shape. Lenses 231 areformed in the first and third corners 2125 and 2128. However, the lenses231 may be formed in any two of the corners, as discussed below.

FIGS. 16 and 17 are plan views showing the horizontal and verticalmovements of the mask 200, during irradiation of a substrate. Themovements are substantially the same as shown in FIGS. 8 and 10, thus,only the difference therebetween will be discussed in detail.

Referring to FIG. 16, the lenses 231 of the first and second sides 2121and 2122 are sequentially disposed in area A. Since these lenses are notoffset 231, lenses 231 from each of the first and second sides 2121 and2122 are sequentially disposed over the same silicon layers. Thus, eachof the silicon layers in region A is irradiated twice. However, due tothe partial light blocking layer 250, only half of the input laser lightreaches the silicon layers during each irradiation, as compared to thesilicon layers disposed below lenses 230.

Thus, when a laser is irradiated twice through the first side 2121 andthe second side 2122, the corresponding silicon layers are crystallized.Similarly, when laser is irradiated twice through the third side 2123and the fourth side 2124, the corresponding silicon layers arecrystallized.

Referring to FIG. 17, the first to fourth corner areas 2125, 2126, 2127,and 2128 of the mask 200 are sequentially disposed in area C. Since onlytwo of the corners include lenses 231, a silicon layer disposed in areaC receives the same amount of laser light as silicon layers disposedunder the lenses 230.

FIGS. 18A, 18B, 18C, and 18D are plan views showing masks 201, 202, 203and 204, that are similar to the mask 200 of the mask of FIG. 13. Assuch, only the difference therebetween will be described in detail.Referring to FIGS. 18A to 18D, the mask 201 includes lenses 231 disposedin the first and second corners 2125 and 2126, the mask 202 includeslenses 231 disposed in the second and third corners 2126 and 2127, themask 203 includes lenses 231 disposed in the second and fourth corners2126 and 2128, and the mask 204 includes lenses 231 disposed in thethird and fourth corners 2127 and 2128.

Since only two of the first to fourth corners 2125, 2126, 2127, and 2128include lenses 231, even though all four corners 2125, 2126, 2127, and2128 are irradiated over the same silicon layer, the silicon layer isuniformly crystallized. In other words, since two of the corners blockthe light, and the lenses 231 in the other two corners transmit only aportion of the input light, the total amount of light received by thecorresponding silicon layer is the same as the amount received by thesilicon layers disposed under the lenses 230.

FIG. 19A is a plan view showing an array substrate 7000 that has beencrystallized using the mask of FIG. 13. FIG. 19B is an enlarge portionof the array substrate 7000 of FIG. 19A. Referring to FIGS. 19A and 19B,the array substrate 7000 includes a pixel area 720 and a peripheral area710. The pixel area 710 is divided into crystallization areas 740 thatare separated by boundary portions 745. The width of the boundaryportions 745 is substantially equal to the width of the sides of theperipheral area 212. The crystallization areas 740 includecrystallization areas A, B, C, and D. The boundary portions 745 includeboundary areas a, b, c, d, and e, which are disposed between thecrystallization areas A, B, C, and D.

When the peripheral area 212 of the mask 200 includes multiple rowsand/or columns of lenses 231, the boundary areas 745 may be wider. Wheneach of the crystallization areas 740 is irradiated with a laser, lightintensity differences may produce brightness variations between thecrystallization areas A, B, C, and D. Thus, when the pixel area 720displays an image having a uniform brightness, the brightness variationsmay produce lines between the crystallization areas A, B, C, and D.

However, when laser intensity variations occur among crystallizationareas A, B, C and D, the boundary areas a, b, c, d, and e include activelayers formed by both intensities. Thus, appearance of brightnessvariation lines is reduced

As described above, according to exemplary embodiments of the presentinvention, laser light is condensed through a lens formed on a mask tocrystallize amorphous silicon, thereby increasing an electron mobilityof a TFT formed on a pixel area, so that the TFT may be formed in asmall size. Thus, a space of the TFT within one pixel may be decreased,so that an aperture ratio of the pixel may be greatly enhanced.

Moreover, in a process that one pixel area is divided into pluralcrystallization areas to be partially crystallized, a peripheral area ofthe mask is shared to be irradiated with laser having the differentstrength for crystallizing, so that a boundary between thecrystallization areas may be reduced. Thus, a luminance difference on ascreen may be reduced.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A mask comprising: a substrate comprising acentral area and a peripheral area disposed around the central area, theperipheral area comprising opposing first and second sides, and opposingthird and fourth sides extending between the first and second sides; andlenses disposed in rows and columns in the central area and in thefirst, second, third sides of the peripheral area; wherein, the lensesof the first side of the peripheral area are disposed in different onesof the rows than the lenses of the second side of the peripheral area,and the lenses of the third side of the peripheral area are disposed indifferent ones of the columns than the lenses of the fourth side of theperipheral area.
 2. The mask of claim 1, further comprising a lensdisposed in a corner of the peripheral area that is disposed between thefirst side and the third side.
 3. The mask of claim 1, furthercomprising a light-blocking layer disposed on the substrate and betweenthe lenses.
 4. The mask of claim 3, when the lenses of the peripheralarea are arranged in an irregular pattern.
 5. The mask of claim 1,wherein in the peripheral area: the lenses of the first side aredisposed in one column; the lenses of the second side are disposed inone column; the lenses of the third side are disposed in one row; andthe lenses of the fourth side are disposed in one row.
 6. The mask ofclaim 1, wherein in the peripheral area: the lenses of the first sideare disposed in at least two columns; the lenses of the second side aredisposed in at least two columns; the lenses of the third side aredisposed in at least two rows; and the lenses of the fourth side aredisposed in at least two rows.
 7. A mask comprising: a substratecomprising a central area and a peripheral area disposed around thecentral area; first lenses disposed in rows and columns in the centralarea, to focus light onto a semiconductor layer; and second lensesdisposed in the peripheral area and in the rows and the columns, tofocus light onto the semiconductor layer, wherein for an equal amount ofinput light, the light focused by the second lenses has a lowerintensity than the light focused by the first lenses.
 8. The mask ofclaim 7, further comprising second lenses disposed in two corners of theperipheral area.
 9. The mask of claim 8, wherein the second lenses arepartially covered by a light-blocking layer.
 10. The mask of claim 8,wherein the second lenses are half-tone lenses.
 11. The mask of claim 7,further comprising a light-blocking layer disposed on the substratebetween the first lenses and the second lenses, wherein thelight-blocking layer partially covers the second lenses.
 12. The mask ofclaim 7, wherein the second lenses are disposed in two rows or twocolumns, on each side of the central area.